I have had my 99 4cyl atx cougar for three years, driven it reliably everyday, and have decided that it is way past tome to do some mods. Most of my experience is working on older vehicles w/o computers, so I need to make sure I don't screw anything up in the process of simple mods. Is there anything special that you have to so to remove that cats and precats, or can I just unbolt them, and run all new exhaust pipes? What about O2 sensors? Thanks for the help. This is the most helpful forum I have ever used. Not only are these great cars, they also have great owners!!!